Locking pivot-plates.



C. L. WILLIS & D. W. RANDALL.

LOCKING PIVOT PLATES.

APPLICATION FILED NOV. 8. 1915.

Patented May 9, 1916.

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CHARLES L. WILLIS LAND DELAVAN W. RANDALL, OF SEATTLE, WASHINGTON.

LOCKING. PIVOT-PLATES.

Specification of Letters Patent.

Patented May 9, 1916..

Application filed November 8, 1915. Serial No. 60,379.

T 0 all whom it may concern:

Be it known that we, CHARLES L. WILLIS and DELAVAN W. RANDALL, citizens of the United States, residing at Seattle, in'the county of King and State of Washington, have invented certain new and useful Improvements in Looking Pivot-Plates; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to buiders hardware, and more especially to hinges which are adapted to lock positively in various positions; and the object of the same is to produce a pair of plates so pivotally connected with each other that one may be slid on the other and the plates locked in various positions. In the accompanying drawings and in the following specification we have illustrated and described one use of these plates which is for connecting the upright side bars of a step-ladder with the upright side bars of its brace, but we do not wish to be limited to this use for it is obvious that such locking pivot plates may be employed in a variety of places with equal advantage. In the use shown and described, it is to be understood that each side bar of the upright and brace is connected by a pair of said plates although but a single pair is illustrated. Furthermore we have shown the plates as of a shape adapting them to this use, although it is obvious that they could be differently shaped for other purposes.

In the accompanying drawings :Figure 1 is a side elevation of a step-ladder showing its two parts as connected by a pair of these plates, and Fig. 2 is a View of these plates from the opposite position showing the back of the female plate or member whereas the face of this plate'or member is shown in Fig. 1. In both these views the plates are locked, but in Fig. 2 they are shown in dotted'line as unlocked- Figs. 3 and 4 are perspective views respectively of the male and female plates or members. Fig. 5 is a side elevation similar to Fig. 2 showing a slight modification.

The step-ladder illustrated in Fig. 1 comprises upright side bars U connected by steps S and a top step or table T, and as usual this much of the step-ladder is held in upright position by a brace whereof the letter B designates one of its side bars. The brace is pivoted near its upper end to the upper end of the side bar of the ladder proper, and when our improved locking pivot plates are applied at this point they permit the swinging of the member B with respect to the member U and the locking of these two members after they have been thus adjusted.

Coming now to the details of the present invention, we have used the letters M and F respectively to indicate what might be called the male and female members or plates constituting the present invention. The male member is substantially a rectangular plate 1 having holes 2 which are counter-sunk on the face of the plate that appears in Fig. 3 so that they will receive screws 8 and permit their heads to lie flush with such face as shown in Fig. 2; and through the center of this plate'is cut an elongated hole or slot 4 whose length is parallel with the length of the plate. Above and below this slot are stops 5 and 6 projecting from the face, and as shown in Fig. 3 these stops are formed by cutting lips out of the sheet metal body of the plate on the line 7 and bending them up. l/Ve might here say that perhaps the cheapest, way of making this device is to form each of the plates of sheet metal, and if so an extremely cheap and simple way of making the stops is to cut them out and bend them up as just described; but we do not wish to be'limited in this respect as the plates and stops may be made of other materials in other ways as will be explained below. In length each stop is perhaps about an inch. The upper stop 5 stands on a line nearly parallel with the axis of the plate 1 and which line if projected would pass through the hole 4, whereas the lower stop 6 stands on a line nearly parallel with the line of the upper stop but offset therefrom and therefore on a line which if projected would pass .the hole 4 as will be seen best in Fig. 2.

The female member F as best seen in Fig. 4 is made of a plate 11 also provided with screw holes 12 which are counter-sunk on its face for the flush reception of screws 13 as seen in Fig. 1, and at its center it has a round bolt-hole 14. Above and below this bolt-hole are formed openings 15 and 16 which are shown in Fig. 4 of substantially sector shape, their outer ends 17 being struck on arcs around the center of the hole 14.

WVhat might be called the inner edges 18 of these openings lie substantially parallel with the axis of the plate 11 and in position to be engaged by the stops 5 and 6 when the plates truly overlie each other with their axes coincident, and what might be called the outer edges 19 of these openings are oblique to the inner edges 18 and in position to be struck by the stops 5 and 6 when the plates or members are adjusted on each other as seen in Figs. 1 and 2. In any event the edges 18 and 19 are radii which, with the arcs 17, make up the sector-shaped openings, save that the tips or points of the sec tors are cut off adjacent the bolt-hole let.

A bolt 20 is passed through the boltholes 4: and 14, its head being indicated in dotted lines in Fig. 1 and its nut 21 being shown in Fig. 2; but it is quite possible that a single bolt could be passed through the holes in the two members shown in Fig. 1 and extended completely across the step ladder and through the two holes in the other members not illustrated in this view. The bolt or pivot, whatever its nature, should fit the hole lt rather closely, and should fit movably within the hole 4 so that the plate 1 may rise and fall on the bolt as will appear below.

The construction shown in Fig. 5 is much the same with the following exceptions: Instead of rather long upbent lips 5 and 6, the male member now has pins 25 and 26 projecting from its face; and instead of sector-shaped openings 15 and 16, the female member F herein has arcuate openings 27 and 28 respectively engaged by said pins, the width of each arc being sufficient to permit the pin to move laterally a little within the opening as well as longitudinally thereof. In either case, however, the outer end of the opening 15 or the upper edge of the arc 27 is provided with notches as 30, 31

r and 32, and the bottom of each notch is just as far from the inner edge of the opposite openings 16 or 28 as the inner edge of its opening 27 is from the outer edge of the opening 28. In other words, when the upper stop enters a notch the lower stop rises ofli the arc of the lower opening as the length of the bolt-slot 4L will permit, but at other times when the upper stop is drawn out of a notch and moves transversely within its opening 15 or 27 the lower stop rides on the arc of the lower opening 16 or 28.

Assuming that a pair of these plates be secured by means of the screws to the inner face of one upright U and the outer face of the corresponding brace B of a step-ladder, with the faces of the two plates overlying or in contact with each other, and the pivot member 20 applied; the operation of this device will now be as follows: To fold the brace alongside the upright, the brace with the male member M is drawn downward so that its stop 5 or 25 diseng-ages the notch with which it was formerly in engagement, and thereafter this member can be swung freely around the pivot and over the female member F. When now the ladder is to be used it is set up and the brace swung open around its pivot, after which it is pushed upward or the side bar U is pushed downward with respect to the base, and the upper end of the upper stop 5 or 25 engages one of the notches 30, 31 or 32, according to the distance the brace has been swung to the rear. It will now be apparent why the arcuate slot 28 is made wider than the diameter of the pin 26, the reason being to give said pin a certain freedom of movement transversely of this slot as the other pin 25 enters one of the notches. Also each upturned lip-shaped stop 5 and 6 is of slightly less length than either side edge 18 or 19 of its respective opening 15 or 16, for the same reason. WVhen this invention is applied to a step-ladder there will not be room to make the two plates 1 and 11 of great length and therefore the stops cannot be very remote from the pi"othence we prefer in this construction to employ upbent or rather long stops or lips 5 and 6. In other cases, and in fact in some instances with step-ladders, it maybe preferred to use pins for the stops as shown at 25 and 26. The former have the advantage that they contact throughout their entire length with one edge or the other edge of the sector-openings, whereas the pins contact only with the ends of the openings as will be clear. o have shown but three notches 30, 31 and 32 in the arcuate or curved edge of the slot or outer end of the opening as the case may be, but it is obvious that a greater number could be em ployed, and it mightin fact-be advisable in any event to have one notch at the inner end or corner as at 33 so that when the brace B is folded alongside the upright U it may be locked in this position by the pivot plates. In the use of this invention on a step-ladder the upper end of one member may be beveled off and the upper end of the other rounded as shown, but this is merely a detail and is employed because the upper end of the upright U is beveled beneath the uppermost step T, and the upper end of the brace 13 will swing on a curve around the pivot.

It is quite obvious that either plate may have whatever contour its use demands, and also that considerable modification in other details may be made without departing from the principle of this invention.

We claim 1. A pair of locking pivot plates whereof one has a round and the other an elongated central bolt-hole and one plate has openings struck on arcs around its hole and above and below the same, the outer edge of one opening having a plurality of notches and the outer edge of the other opening being smooth, a bolt through said holes permitting pivotal and longitudinal movements of the plates upon each other, and stops projecting from one plate into the openings of the other and of a size and location to permit both said movements and to permit one of the stops to be moved into contact with said smooth edge and disengaged with any notch or moved out of such contact and engaged with any of said notches, for the purpose set forth.

2. Two elongated plates, a pivot at about their mid-length loosely connecting the plates so as to permit their relative longitudinal movements, the first plate above. the pivot having an opening of substantially sector shape with its edges radial to the hole and its arc concentric thereto and notched, and below the pivot another substantially sector-shaped opening of the same size as the first but laterally offset within the plate so that its edges are not radial to the hole, and the second plate lying face to face upon the first and having above the pivot an elongated upstruck lip projecting into the upper opening and of the same length as either edge thereof, and below the pivot an other elongated lip parallel but out of alinement with said first lip, said second lip projecting into the lower opening and shorter than the edges thereof, all for the purpose set forth.

3. An elongated plate having at its midlength a hole, above the hole an opening of substantially sector shape with its edges ra-- dial to the hole and its arc concentric thereto and notched, and below the hole another substantially sector-shaped opening of the same size as the first but laterally offset within the plate so that its edges are not radial to the hole; combined with a second elongated plate lying face to face upon the first and having at its mid-length a hole elongated longitudinally of the plate, above the hole an elongated upstruck lip projecting into the upper opening and of the same length as either edge thereof, and below the hole another elongated lip parallel but out of alinement with said first lip, said second lip projecting into the lower opening and shorter than the edges thereof; and a pivot through said holes, all for the purpose set forth.

4. Two elongated plates, a pivot at about their mid-length loosely connecting the plates so as to permit their relative longitudinal movements, the first plate above the pivot having an opening of substantially sector shape with its edges radial to the pivot and its arc concentric thereto and notched, and below the hole another substantially sector-shaped opening, and the second plate lying face to face upon the first and having above the pivot an elongated upstruck lip projecting into the upper opening and of the same length as either edge thereof, and below the pivot another elongated lip projecting into the lower opening and shorter than the edges thereof, all for the purpose set forth.

5. A plate having a hole, above. the hole an opening of substantially sector shape with its edges radial to the hole and its arc concentric thereto and notched, and below the hole another substantially sector-shaped opening; combined with a second plate lying face to face upon the first and having a hole elongated longitudinally of the plate, above the hole an elongated upstruck lip projecting into the upper opening and of the same length as either edge thereof, and below the hole another elongated lip projecting into the lower opening and shorter than the edges thereof; and a pivot through said holes, all for the purpose set forth.

6. A pivot comprising an oblong sheet metal plate having a hole through it at about the center of its length, substantially sectorshaped openings above and below the said hole and with the arc of the upper opening notched, and screw holes through its body around its edges; a second oblon sheet metal plate having a central bolt-hole elongated longitudinally of the plate, unbent lips above and belowthis hole and adapted to engage said openings, and screw holes around its edges; and a bolt passing through and fitting in the hole of the first plate and loosely engaging the hole of the second plate, the whole constructed for use substantially as described.

In testimony whereof We aflix our signatures.

CHARLES L. WILLIS. DELAVAN W. RANDALL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of ratents, Washington, D. 0." 

